US1554723A - Tunneling machine - Google Patents

Tunneling machine Download PDF

Info

Publication number
US1554723A
US1554723A US698551A US69855124A US1554723A US 1554723 A US1554723 A US 1554723A US 698551 A US698551 A US 698551A US 69855124 A US69855124 A US 69855124A US 1554723 A US1554723 A US 1554723A
Authority
US
United States
Prior art keywords
conveyor
tunnel
screw
ring
tunneling machine
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US698551A
Inventor
William E Hamilton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US698551A priority Critical patent/US1554723A/en
Application granted granted Critical
Publication of US1554723A publication Critical patent/US1554723A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/12Devices for removing or hauling away excavated material or spoil; Working or loading platforms
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/10Making by using boring or cutting machines

Definitions

  • the smaller shield section 26 has at its rear end ananchoring wheel, yor segmental annular brace similar to the anchoring rim
  • This anchoring ring or brace at the rear of the shield section is for the screw bar 86, and is made up of four spaced segments 57 that are designed to impinge outwardly against the cut walls of the tunnel, as shown in Fig. 8, and each of these segments has a sectional screw bar 58, of which the threads are turned in opposite directions for the hand wheels 59.
  • the diagonal braces 58 are pivoted ⁇ at one end to a segment and at the other end to a stationary housing 60, by means of the perforated ears 61 thereon. Hooks 62 (see Figs.
  • a multiple of jet sprays 83 spraying cold water on the face of the rock while it is still hot from the passage of electric heat.
  • the heating spraying and chipping mechanism are shown in multiples of four (Figs. 27 and 28) all mounted on the framework of spider-ring V82 which would be mounted on the end of the screw feeder and become a part of the tunneling machine.

Description

Sept. 22, 1925. 1,554,723
W. E. HAMILTON TUNNELING MACHINE Filed Minh '11. 1924 5 Sheets-Sheet 1 WILLIAM EHAM|LTN BYr` Sept. 22, 1925. 1,554,723 W. E. HAMILTON TUNNELING MACHNE Filed March 11. 1,924 -5 Sheets-Sheet 2 Sept. 22, 1925.
W. E. HAMILTON TUNNELING MACHINE Filed arch 11. 1924 5 SheetsSheet Edi Q) WBLLIAM EI HAMILTDN BY Sept. 2z, 1925.
l w. E. HAMILTN TUNNELING MACHINE Filed March' 11. 1924 5 Sheets-Sheet 5 WILLIAMI EHAMILTUN Patented Sept. 22, 1925.
UNITED STATES WILLIAM E. HAMILToMbF COLUMBUS, oIIIo.4
TUNNELING MACHINE. Y
Application filed March 11, 1924. Serial N o. 698,551.
To all whom t may concer/a.'
Be it known that LVVILLIAM E. HAMILTON, a, citizen of the United States of America, residing at Columbus, in the county of F rankliii and State of Ohio, have invented certain new and useful Improvements in Tunneling Machines, of which the followiiig is a specification.
VThe present `invention relates to improvements in. tunneling machines for boring tunnels, sewers, and other subterranean excavations, and the machine of the invention is adapted for boring in different kinds of materials, may be adapted for boring different diameters of tunnels, and provides means for removing the spoil, and also for furnishing the building material to be used inY the construction of tlie wallsof the tunnel. In boring the tunnel underground, a vertical shaft is used, and the deviceembodies means for extending the operations forward from the vertical shaft, and for returning tlie spoil or excavated material to the bottom of the shaft. The building material is carried forward from the bottom of the vertical shaft to the tunneling machine ,by the same conveyor that is employed to carry away the spoil.
In the preferred embodiment `of the in-v vention, a vertically disposed rotary cutter is employed to cut yintotlie face of the tunnel head, and a spiral or screw conveyor is utilized to convey the spoil from the cutter head to an endless conveyor which extends back to the vertical shaft.
The vertical shaft is equipped with an endless elevator by which the material excavated. is lifted to the surface of the ground and emptied into a hopper from which it is carried away by suitable vehicles.
The invention consists in certain novel constructions and arrangements of parts'as will be hereinafter more specifically pointed out and claimed.
In the accompanying drawings, I have illustrated one complete example of the physic-al embodiment of my invention, together with several modified forms of the horizontal rotary cutter, andthe parts are combined and arranged according to the best mode I have so far devised for the practical application of my invention.
Figure l is a sketch showing the tunnelused in connection therewith F ig. 4:- isan enlarged detailview, showing the tunnel in section, and illustrating the boot of the elevator, together wth the outgoing and the incoming members Aof the horizontal conveyor.
`F ig. 5 is an. enlarged detail view ofthe tunnel-ing machine in telescoped position, the cutter being retracted, and ready to be fed forward as it cuts intothe face of the tunnel.
Fig. 6 is a view similar to F ig, 5, but here the cutter has bored into the tunnel head and is in extended position.
Fig. 7 is a view in end elevation of a cutter head that is used in clay or soft material.
Fig. 8 is a plan View of the machine in the position of Fig. 6.'
Fig. 9 is an end elevation of the machine of Figs. 5 and 6, the view beingntaken from the right end.
Fig. 10 is aside elevation, partly in section, of the expanding ring that is used as a base for guiding the direction. of bore of the cutter.
Fig. 11 is an end elevation, showing the segmental arms of the guiding ring of Fig. IO
Fig, 12` is a side elevation showing the truck which supports the idler sprocket or tail wheelof the conveyor, and also showingin side elevation an anchor ring fitted against the walls of the completed tunnel.
Fig. 18 isa view in elevation, `from the yleft of Fig. 12, showing the `anchor ring,
whichV is similar to the ringin Fig. 10.-
lF ig. 14 is a view in leleva-tion from the right end in Fig. 12.
Fig. 15 is a side elevation of a part ofthe horizontal endless conveyor trough, and carriers. Fig. 16 is a view from the right endvof Fig.d15. i
Fig. 17 is an enlarged detail sectional vfor hard spoil'.v
view of the screw-drive mechanism of the rotary cutter, by means of which the tunneling machine is contracted or telescoped after each boring operation of the machine.
Fig. 18 is* an -enlargeddetail'sectional view through one ofthe conveyor troughs, l
this trough being for the outgoing excavated spoil. v
Fig. 19 is a similar view showing the troug'h for the incoming` building material. Fig. 2O is a view showing one of the standard sections of the conveyor cable, which vpasses through Lthe troughsof Figs.
y 18a-miie. I Fig. .21 is a :modified form showing a tal pered or conical cutter head.
-Fig. 22 is an end jview showing the tapered cutter head ofFig. 21.
Fig. 23 is an enlarged transverse sectional l View through .the framework and thecutter blade of jthe cutter in Fig. 121,
'Fig'. 24 is a side view of a modified-form of tapered cutter ihead, especially adapted Fig. 25 is an enlarged detail of the iframing of the head in F 24, showing the` diagrammatically, and the different features of the 'entire `apparatus may be yhere described, in order to give 4aclear understanding `of theinvention. y
The partly completed tunnel is indicated by the Vletter T, and the intersecting vertical shattis lettered S, there being a hopper ll at the Amouth of the shaft togreceive the excavated spoil from the vertical endless conveyor 1 operated by the motor 2, and equipped with buckets 3. n The conveyor travels in 'a housing 4,k and elevates the spoil to the hopper H 'from which it is emptied 4into the waiting truck R.
The 'tunneling lmachine, orcntting machine is designated M, and the khorizontal conveyor C receives the spoil from a, screw .coni'zeyor B., which latter conveyor receives the spoil direct from the cutting'device of theJ tunneling machine.
The horizontal conveyor C is made up of transverse holsters 5, in which are supported `the two-wheeled trucks 6, the-wheels being beveled so that they may xreadily travel, and
rest solidly on the curved bottom of 'the completed tunnel. These holsters 5 are con-y nected by a pair Io troughs-as 7 and 8, the Jformer 'being for outgoing material, .and
the latter for incoming'building material.
The cable conveyor sections 9 (see Fig. 20) are provided with disks 10 that slide along in the troughs, and the outgoing` trough 7 conforms to the circular disk, sothat the material may be conveyed etliciently through the trough. The incoming trough which forms a channel for the brick, stone, and
Vother material, has `flattened side walls,
adapting them to the material that is carriedl from the shaft to the tunneling machine. The section oi cable 9 in Fig. 20, in actual use, is twice the length of the section of the conveyor illustrated in Fig. 15. That is, the distance from one truck '6 `to the adjoining truck 6 is half the dist-ance of the cable section 9. Thus, as the boring progresses, the conveyor may be elongated by addingl the sections to the .tail end of the conveyor and pushing the 'entire conveyor forward on its wheels 6. The troughs 7 and 8V are suitably fastened to the holsters 5, and arch barsll are erected -transversely offthe `holsters to brace the structure.
top of the arch bars, and transverse brackets 13 are fastened-between these angle bars. Theftransverse bars 13 4are adapted to support wires, pipes, tubes, etc., which torni part of the equipment of the apparatus.
The horizontal conveyor cable is stretched between the horizontal head sprocket wheel 14, and the tail sprocket wheel 15. The wheel 15 is an `idler supported on the truck 16 `at ther rear of the conveyor, and this truck is anchored by and at the rear of the anchoring ring which is made up of four segments 17 thatI impinge against the `inner wall of the cylindrical tunnel. These segments are arranged in pairs that are connected by screw bars 18, 19, and the screw bars, which. are threaded in opposite directions, are provided with hand-wheels 20, by means of' which the bars may be protracted toA anchor the ring in the collar, or contracted to withdraw the ring from engagement with 4the wall ot the tunnel. The truck 16 is held out from the anchor Aring by diagonal braces 21, pivoted to the ring segments and to the truck, as best seen in Fig. 12.V
In'Fig, 8, it will be seen that the trough Sterininates ina wide mouth 2v2 just back of the tunneling machine, and the cable conveyor passes vtherefrom and `around the head wheel 414. The trough 7 (the outgoing trough) has a rounded end 23 and a short leg 24 (Fig. 8) for guiding the cable conveyor around the head of the conveyor and through the short leg, and the disks 1() of the conveyor.successively carry away the spoil as it is deposited in the trough 7 by the spiral or screw conveyor B, operating in its trough 24.
The tunneling machine proper is encased within a telescopic housing or shield made Longitudinal angle bars 12 kare bolted near the `for the spiral conveyor.
up of the two cylindrical, metallic sections 25 and 26, rollers 27 being employed on the outer and inner sides of the respective sections, as anti-friction means, and for guiding the telescopic members during the extension, and contraction of the machine. The rear end of the shield is open, but the head end is closed by a partition 28, although in some of the views of the drawings this partition is broken away. In front of the partition is a space 29 for the rotary cutter head. The cutter head in Figures 5, 6 and 8 includes the crosshead 29 from the ends of which. project the oblique arms 80, upon which are mounted the diametrically arranged two pairs of cutting blades, 31 and 32, andthe material is brokeirdown between the diametrically opposite` cutting blades and 'the radial blades 38, of the cross-head and force Y the dirt or spoil through the opening 34 vin the partition 28, and into the spiral conveyor trough 24, and from thence the spoil is carried to the outgoing side of the cable conveyor and through its trough to thev boot 35 of the elevator. i
The cutter head is carried on the end of the screw bar 36 of the tunneling machine, and power is transmitted from this screw bar to the spiral conveyor through the medium of the sprocket 87 on the screw bar, sprocket chain 38, and sprocket wheel 39 on the shaft 40 of the spiral conveyor.
The screw bar is supported between the frame members 41 and 42 that are rigidlyV fixed in the section 26 of the shield, and is revolved from the electric motor 43 by the .train of gears 44, 45, 46 and 47 the last gear being keyed to the screw bar which is grooved to permit longitudinal movement of the bar through the gear (see Figs. 6 and 8).
rlie gear is fixed on the counter-shaft 48, and the clutch device 49 is `adapted to control and operate the cutter head.
A clutch device 50 on the shaft 48 controls `the driving mechanism for the cable con- `stub shaft 56 of the gathering wheel or head wheel 14 of the conveyor.
kThe smaller shield section 26 has at its rear end ananchoring wheel, yor segmental annular brace similar to the anchoring rim This anchoring ring or brace at the rear of the shield section is for the screw bar 86, and is made up of four spaced segments 57 that are designed to impinge outwardly against the cut walls of the tunnel, as shown in Fig. 8, and each of these segments has a sectional screw bar 58, of which the threads are turned in opposite directions for the hand wheels 59. The diagonal braces 58 are pivoted` at one end to a segment and at the other end to a stationary housing 60, by means of the perforated ears 61 thereon. Hooks 62 (see Figs. 5,- 6 and 8) areemployed to guide the screw bars or braces 58 `at the periphery of the housing section 26, and the screw bars are pivoted to the segments at 68. The rotary cutter is operated from the motor through the screw bar 86, and as the cutting progresses, the rotary cutter with the outer shield section 25, is projected ahead of and away from the shield` section 26, and the machinery therein, the extended position of the machine being shown in Fig. 8. After each' cutting operation, whereby the sections are moved with relation to each other, i. e., after the section 25 is projected from the section 26, and the cutter head is projected from its drivingmachinery, the section 26 is pushed forward, together with the driving machinery, insidethe section 25 to the position shown in Fig. `5.
For directing the bore of the tunnel in either a straight line or for deflecting the directionof the tunnel in a curved line, the diagonal or radial braces 58 and hand wheels 59 are used in conjunction with the segments 57, to set the screw bar 36 in the desired direction.
The forward feed drive for `the cutter head utilizes the clutch 68, on shaft 48, which when thrown in, transmits power from the shaft 48 through the` large gear wheel 64 to the smaller wheel 65, the latter on the stub shaft 66, in the housing. 60. This shaft 66 has thereon a pinion 167 that engages thev gear 68 threaded on the screw bar 36. The gear 68 is retained in the housing 4against movement, laterally, and therefore when the clutch 63 is thrown in, the screw drive is operated, and` in this position the/rotary cutter is again ready to operate, and the boring continues. kEach `time that the machine is moved forward, the conveyor cable is elongated a corresponding distance, and the work thus proceeds step by step until the destination is reached. 1
After the end of each forward operation of the cutter head and consequent advance of the screw with relation to its machine, the machine is advanced and with it the cylinder 26 is telescoped in the larger cylinder shield 25. In Fig. 6, where the cutter head is advanced, rear braces 69 with feet 70 to engage the end of the completed tunnel, are employed. These braces are pivoted at 7l to a bearing cup 72, which fits over the rear end of the screw bar. The expanded ring brace is now loosened and onlythe clutch 63 is thrown in with the result that the section 26 and its machinery, are carried forward and telescoped within section 25 to the position of Fig. 5.
Figures 21, 22 and 28 show views of a modified form of cutter headwhich has a centering auger 74, and this auger together the different described cutter heads in which the long blade on each sidehis .omitted and replaced by a more narrow cutting blade 7 8 to be used in excavating hard shale and formations in'which boulders may occur. In this `structure the cutter can be manipulated to operative position by Vmeans of the hand wheel 79 s-hown in Fig. 25, and thus cut around the boulder andv allow it to lbe dislodged by hand without damage vto the machine. f
In Figure 26 amethod-of adjusting the critter head laterally r is illust-rated by means of the bolt 80, and in Figure 25 means for adjusting it longitudinally comprises .a hand wheel 79.
I/Vhen excavating very hard or vitreous rocks I utilize an electrical cutter head as illustrated in Figure 27 and alternately heat and cool the rock to be excavated in a circular or annular path which is the diameter of the tunne-l bore. This method of eX- cavating is accomplished as indicated in Figures 27 and 28 by passing aI low voltage electric rcurrent between the two electrodes shown as the four sets of wheels 81 on the cutter head or ring 82. As `the cutter head slowly revolves the electric current passing from one electrode wheel to the other goes through the stone having a high resistance, and by thisineans the stone is brought to a high heat. If necessary the face offthe rock may be sprayed with'bicarbonate of soda. or other material to make it fusible.. Immediately following the electrode wheels is a multiple of jet sprays 83 spraying cold water on the face of the rock while it is still hot from the passage of electric heat. By this means of Suddenly cooling the rock it may be caused to crack and chip thus readily enabling the chisel cutters 84 immediately following ythe water jets to dis-y lodge the broken pieces. The heating spraying and chipping mechanism are shown in multiples of four (Figs. 27 and 28) all mounted on the framework of spider-ring V82 which would be mounted on the end of the screw feeder and become a part of the tunneling machine.
IVhat I claim is:
l. The combination with a tunneling machine including a. rotary cutter head, aspiral riers on said sections, and an endless -ele vator co-acting with said conveyer.
2. The combination witha tunneling machine of a conveyer to receive spoil therefrom, a trough for outgoing spoil and a trough for incoming building material, an endless conveyer traveling in said troughs, and an endless vertical elevator at the lrear of the endless conveyer.
3. The combination in a tunneling machine including a rotating cutter head and a transporting conveyer comprising parallel troughs, an yendless cable traveling through said troughs and provided with spaced carrier disks whereby one .troughand one branch of the conveyor bring in construction material, an initial feeding device for the conveyor, and an elevator at the rear of the transporting conveyor.
4. The combination with a tunneling machine, of a transporting conveyor including an endless cable, of an anchoring truck and a tail wheel thereon for the conveyer, ya segmental expanding ring fforwazrd of the truck adapted to engage the walls of the tunnel, and a bracer between said .ring and the truck.
5. .'Ihecombination with a tunneling Inachine of a transporting conveyor including an endless conveyor cable and head and tail wheels therefor, an anchoring truck for the tail wheel, an anchoring ring forward ofthe truck to engage the walls of the tunnel, means for expanding the anchoring ring and :means connecting the `ring with the truck.
6. The combination with an endless conveyer of an anchoring truck, an anchoring ring, and operating. means for the conveyor including a tail wheel on the truck, said ring comprising curved vsegment-s to engage the wall of a tunnel, sectional screw bars engaging the segments in pairs and a hand a rotary screw bar supported in the inner member of the housing, the screw bar and operating' means therefor, and means co-operating with the screw bar for advancing the inner member and contained machinery after a Iperiod of operation by the critter. y
8. The combination in a tunneling machine including a rotary cutter' head and screw bar, and o-perating machinery for the screw bar, supporting means for the end of the bar,`an anchoring ring for the machinery including curved segments, and adjustable means connecting said segments with the screw bar Aco--operating with said supporting means for governing the direction of the travel of the cutter head.
9. The combination in a tunneling maa rotary cutter on' chine including a rotary cutter head and screw bar, and operating machinery for the screw bar, supporting means for the end of the bar, an anchoring ring for the maehinery including curved segments, radat? ing sectional screw bars connecting said screw bar With the anchoring ring, and
ing means to guide the direction of the 10 travel olf the cutter head.
` In testimony whereof I haveaffxed my signa-ture.
WILLIAM E. HAMILTON.
US698551A 1924-03-11 1924-03-11 Tunneling machine Expired - Lifetime US1554723A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US698551A US1554723A (en) 1924-03-11 1924-03-11 Tunneling machine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US698551A US1554723A (en) 1924-03-11 1924-03-11 Tunneling machine

Publications (1)

Publication Number Publication Date
US1554723A true US1554723A (en) 1925-09-22

Family

ID=24805731

Family Applications (1)

Application Number Title Priority Date Filing Date
US698551A Expired - Lifetime US1554723A (en) 1924-03-11 1924-03-11 Tunneling machine

Country Status (1)

Country Link
US (1) US1554723A (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2548952A (en) * 1948-08-27 1951-04-17 Crossland Alfred Coal mining and conveying machine
US3382002A (en) * 1965-07-23 1968-05-07 John R. Tabor Rotary cutter wheel tunneling machine
US3411826A (en) * 1966-05-26 1968-11-19 Smith Ind International Inc Tunnel boring machine
US3413033A (en) * 1966-09-09 1968-11-26 Smith Ind International Inc Rotary tunneling machine having improved debris disposal means
US3677602A (en) * 1970-02-24 1972-07-18 John R Tabor Tunneling machine with concrete wall forming mechanism
US3778107A (en) * 1972-01-03 1973-12-11 Ameron Inc Remote-controlled boring machine for boring horizontal tunnels and method
US3796463A (en) * 1970-10-20 1974-03-12 Environment One Corp Process and apparatus for mining by hydroelectric pulsed liquid jets
US3826537A (en) * 1970-12-21 1974-07-30 Copper Range Co Mining and tunneling process involving alternated application of thermal and mechanical energy
US3861749A (en) * 1970-07-08 1975-01-21 Gewerk Eisenhuette Westfalia Mineral mining installations
US3870368A (en) * 1973-05-23 1975-03-11 Dresser Ind Tunneling shield
US3979921A (en) * 1973-05-23 1976-09-14 Dresser Industries, Inc. Tunneling shield

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2548952A (en) * 1948-08-27 1951-04-17 Crossland Alfred Coal mining and conveying machine
US3382002A (en) * 1965-07-23 1968-05-07 John R. Tabor Rotary cutter wheel tunneling machine
US3411826A (en) * 1966-05-26 1968-11-19 Smith Ind International Inc Tunnel boring machine
US3413033A (en) * 1966-09-09 1968-11-26 Smith Ind International Inc Rotary tunneling machine having improved debris disposal means
US3677602A (en) * 1970-02-24 1972-07-18 John R Tabor Tunneling machine with concrete wall forming mechanism
US3861749A (en) * 1970-07-08 1975-01-21 Gewerk Eisenhuette Westfalia Mineral mining installations
US3796463A (en) * 1970-10-20 1974-03-12 Environment One Corp Process and apparatus for mining by hydroelectric pulsed liquid jets
US3826537A (en) * 1970-12-21 1974-07-30 Copper Range Co Mining and tunneling process involving alternated application of thermal and mechanical energy
US3778107A (en) * 1972-01-03 1973-12-11 Ameron Inc Remote-controlled boring machine for boring horizontal tunnels and method
US3870368A (en) * 1973-05-23 1975-03-11 Dresser Ind Tunneling shield
US3979921A (en) * 1973-05-23 1976-09-14 Dresser Industries, Inc. Tunneling shield

Similar Documents

Publication Publication Date Title
US2694562A (en) Apparatus for continuously digging coal
US1726963A (en) Mining and loading machine
US1554723A (en) Tunneling machine
US2734731A (en) Mining machine
US4043137A (en) Apparatus for and a method of constructing a tunnel
AU598335B2 (en) Method of excavation and apparatus therefor
US3362752A (en) Mining apparatus and method
US1674870A (en) Tunneling machine
US4131317A (en) Mining machine having advancing mine roof supports
US2988348A (en) Rotary tunneling machines
US2777681A (en) Mining and loading machine with upper and lower relatively movable disintegrating head portions
US3268258A (en) Conveying and roof bolting method and apparatus
US3052454A (en) Mining apparatus having coring and bursting head swingable in horizontal planes
US3467436A (en) Tunnelling machine with rotatable cutter carrying arm for 360 cutting
US1645007A (en) Mining machine
US3506310A (en) Boring machine
US4076316A (en) Continuous mining machine with laterally movable cutter drum member
US3088718A (en) Continuous mining machine
US3337269A (en) Planer mining machine with separate adjustable height rotary machine
US2077432A (en) Apparatus for mining coal
US2134478A (en) Tunneling machine
US1644943A (en) Mining machine
US3061289A (en) Rotary head tunneling machine
US1116356A (en) Coal-mining apparatus.
US1580001A (en) Excavating apparatus